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Feb. 27, 2012 -- Atrial fibrillation (AF), an irregular heart rhythm, is known to increase a person’s risk of stroke. Now, new findings suggest that some people with AF who also have other heart disease risks may be more likely to develop memory problems that may make daily living more difficult.

The findings appear in the Canadian Medical Association Journal.

About 2.2 million adults in the United States have AF, according to the Heart Rhythm Society. When a person has AF, blood is not pumped efficiently through the heart and may pool and clot. If a clot dislodges and travels toward the brain, a stroke may occur.

The new findings do not apply to everyone with AF. “This study was done in a high-risk group of older people with heart attack, stroke, or diabetes,” says researcher Koon Teo, MBBCH, PhD. He is chief of the cardiology service at McMaster University Medical Centre in Hamilton, Ontario, Canada. “We don’t want people in their 30s or 40s with AF to panic.”

But “if you have AF and other risk factors, you should be aware that you may be more likely to develop [mental] problems and have difficulty taking care of yourself and performing activities associated with living independently.”

Large Study, Strong Association

Researchers analyzed data from two studies that included more than 31,000 people from 733 centers in 40 countries. Participants were aged 55 years or older with heart disease or diabetes. Of these, 1,106 had AF when the study began. An additional 2,052 developed AF during the course of the study.

More people with AF than without showed signs of mental decline and had problems performing activities of daily living, such as showering, dressing, and feeding themselves. They were also at greater risk for being diagnosed with dementia than their AF-free counterparts.

More Research Needed

Sumeet Chugh, MD, says the new findings are intriguing, but it is too early to draw any firm conclusions about AF and risk for mental problems. He is an associate director of the Cedars-Sinai Heart Institute in Los Angeles. “This is merely an association and can’t show cause and effect,” he says.

Exactly what could cause memory problems among people with AF is not fully understood, but people with AF may have a series of tiny, undetectable strokes that could result in the mental impairment.

“It is also too early to say that treating AF can lower risk for [mental] decline among those who may be predisposed. It is possible, but we can say that for sure,” Chugh says.

Robert J. Myerburg, MD, says the new study asks many more questions than it answers. He is a cardiology professor at the University of Miami Miller School of Medicine. “The best that we can say is that there is an association, but whether AF is the cause is unclear.”